Various physiologic signals are often recorded and analyzed. These signals may include digestive pH signals, various digestive motility signals, pressure signals, EEG signals and EMG signals, to list only a few.
Typically, physicians require the concurrent recording of a variety of physiologic signals. For example, gastric pH signals are often collected at the same time as pressure signals. Through the concurrent collection of various parameters the physician may better understand the patient's condition.
Ambulatory recording and recorders are widely used to collect such data. Such devices include the Digitrapper Mk III.TM. ambulatory recorder from Synectics Medical AB, the GastroScan II.TM. from Medical Instruments Corporation, and the SuperLogger.TM. from Sandhill Scientific. These types of devices make it possible for patients to remain at home, or at the least be ambulant in a hospital setting while physiological data is recorded. Typically the devices comprise a lightweight recorder in which the desired physiological data signals are temporarily stored and later downloaded for future analysis.
Many types of physiological data may be recorded, including ECG data (Electrocardiogram), EEG data (Electroencephalogram), and pH or pressure data (Motility) in the gastrointestinal tract. Preferably such a recorder should be able to record among a programmable number of channels at a variety of programmable frequencies.
Among the problems associated with current recorders, however, is energy usage. Such recorders, because they must be ambulatory, are battery powered. Thus an ambulatory medical recorder must minimize energy usage while performing almost constant sampling across a variable number of channels at one or more frequencies.